用液氮作为冷却液对调质态42CrMo钢进行磨削淬火试验, 之后对试验钢进行空冷和深冷处理, 研究了淬硬层的组织、硬度和表面粗糙度, 并将其组织与乳化液冷却磨削淬火试验钢的淬硬层组织进行对比。结果表明: 与乳化液冷却磨削淬火相比, 液氮冷却磨削淬火后, 淬硬层中的马氏体更加细小; 深冷处理后, 淬硬层中的的马氏体和碳化物增多; 随着磨削深度增加, 液氮冷却磨削淬火试验钢淬硬层的厚度、峰值显微硬度和表面粗糙度均增大。

Grinding hardening test of 42CrMo steel in quenched and tempered state was carried out by taking liquid nitrogen as cooling fluid, and then, the tested steel was treated respectively by air cooling and deep cooling.The microstructure, hardness and surface roughness of strengthened layer were studied, and the microstructure of strengthened layer was compared with that of the strengthened layer with emulsion cooling grind-hardening. The results show that, after liquid nitrogen cooling grind-hardening, martensite in strengthened layer was more tiny comparing with that in strengthened layer with emulsion cooling grind-hardening; After deep cooling treatment,the numbers of martensite and carbide in hardening layer increased; After liquid nitrogen cooling grind-hardening, with the increase of grinding depth, the thickness, highest microhardness and surface roughness of the strengthened layer were all increased.